Semiconductor Optoelectronics, Volume. 46, Issue 2, 350(2025)
Bolt Stress Testing Method Based on Fiber Bragg Grating Laser Sensing
In this study, a bolt stress test method based on Fiber Bragg Grating (FBG) sensing is proposed to solve the problems of loosening and creep of bolts in long-term service. First, a femtosecond-laser processing technology was used to fabricate an FBG through fiber coating, and an erbium-doped fiber laser with a linear cavity structure was designed based on the fiber grating to achieve a laser output with a high signal-to-noise ratio. Second, bolt gaskets of different sizes made of stainless steel and aluminum were designed and fabricated, and their mechanical characteristics were simulated and analyzed. Next, the FBG was embedded in the stainless steel and aluminum gasket grooves and combined with the bolts to build a stress test system. Applying stress to the surface of the gasket deformed the FBG was accordingly, causing the laser wavelength to drift. In the experiment, stress of 0~10 N·m was applied to the bolt strain test system made of stainless steel and aluminum gasket with groove depths of 1 and 1.5 mm. As the stress increased, the laser wavelength showed a red shift, and the center wavelength of the stainless steel and aluminum washer sensors with groove depths of 1 mm moved by 41 and 61.8 pm, respectively; their sensitivities were 4.05 and 6.13 pm/(N·m), respectively. The 1.5 mm groove-depth stainless steel and aluminum gasket sensors showed wavelength drifts of 141.7 and 180.5 pm, respectively, and sensitivities of 14.12 and 18 pm/(N·m), respectively, along with a linearity of 0.99.
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HUANG Junyi, HE Wei, LI Shaode. Bolt Stress Testing Method Based on Fiber Bragg Grating Laser Sensing[J]. Semiconductor Optoelectronics, 2025, 46(2): 350
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Received: Nov. 29, 2024
Accepted: Sep. 18, 2025
Published Online: Sep. 18, 2025
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